July 4, 2008

Researchers study woman who acquires new accent after stroke

By Jane Christmas

    Karin Humphreys, assistant professor in the Department of Psychology, Neuroscience & Behaviour, and Alexandre Sevigny, associate professor of cognitive science in the Department of Communication Studies & Multimedia. File photo.
A woman in southern Ontario is one of the first cases in Canada of a rare neurological syndrome in which a person starts speaking with a different accent, McMaster University researchers report in the July issue of the Canadian Journal of Neurological Sciences.

The puzzling medical phenomenon known as foreign-accent syndrome (FAS) arises from neurological damage, and results in vocal distortions that typically sound like the speaker has a new, "foreign" accent.

This particular case, however, is even more unusual because the English-speaking woman did not acquire an accent that sounds foreign, but one that instead sounds like Maritime Canadian English.

Rosemarie Dore was recovering from a stroke two years ago, when her family noticed a change in her speech. They asked medical personnel at the Integrated Stroke Unit of Hamilton General Hospital why their mother was suddenly speaking with what sounded like a Newfoundland accent. It was at that point that the medical team joined forces with researchers in McMaster's Cognitive Science of Language program to study the case.

"It is a fascinating case because Rosemarie has never visited the Maritimes, nor has she been exposed to anyone with an East Coast accent," says one of the study's authors, Alexandre Sevigny, associate professor of cognitive science in the Department of Communication Studies & Multimedia at McMaster University. "Her family lineage is Irish and Danish, and neither of her parents ever lived anywhere but in southern Ontario."

Karin Humphreys, the principal investigator in the study, and an assistant professor in McMaster's Department of Psychology, Neuroscience & Behaviour at McMaster University, says that while the new accent was apparent to the woman's family, the woman could not detect the changes herself. Despite intensive speech therapy, the new accent persists, even two years later.

"Rosemarie's speech is perfectly clear, unlike most stroke victims who have damage to speech-motor areas of the brain," says Humphreys. "You wouldn't guess that the speech changes are the result of a stroke. Most people meeting her for the first time assume she is from out East. What we are seeing in this case is a change in some of the very precise mechanisms of speech-motor planning in the brain's circuitry."

Sevigny says Rosemarie's speech after the stroke became slow, and included changes in phonological segments (using "dat" for "that", and "tink" for "think") as well as the opening of some vowels and diphthongs ("greasy" was pronounced "gracey", and "dog" was pronounced to rhyme with "rogue".)

Humphreys says the research makes her wonder whether FAS might be under-reported because doctors rely on family members to alert them to speech changes post-stroke.

"Promoting multidisciplinary interactions with other Faculties is a strategic priority for the Faculty of Science," said John Capone, dean, Faculty of Science. "Partnerships like that between Dr. Humphreys in Science and Dr. Sevigny in Humanities is a great example of how research collaborations across disciplines often result in important findings that otherwise may have remained obscure."

Funding for the study was provided in part by a grant from the Natural Sciences and Engineering Research Council.